基于信息熵的城市边缘区的界定方法研究——以南京市为例

城市边缘区是城乡共同作用的地域单元。如何及时、准确地划分城市边缘区,是目前研究在GIS和RS相关软件的支持下,以南京地区2003年的Landsat TM遥感影像为计算依据,以信息熵理论为基础,结合分析城市边缘区土地利用特征,改进了传统的土地利用信息熵模型,分析熵值分布特点,最后采用突变检测的方法,以熵值60和68确定南京城市边缘区内、外边界的位置,划定了南京城市边缘区的大致范围。研究认为城市边缘区边界是动态变化的;在城乡断面上城市边缘区的景观紊乱度明显高于城市核心区和城市影像区,这为客观划分城市边缘区和利用遥感影像监测城市边缘区的动态变化提供了一个新的途径。

A method of division of urban fringe based on message entropy-A case study in Nanjing city

Urban fringe is a spacial unit with interaction of urban and rural areas. So far how to identify urban fringe from urban area and rural areas is one of the major fields that the circle of urban geography concerns. In this paper, remote sensing images of Nanjing district in 2003 was the calculating base. At the same time, the RS and GIS softwares were applied to program and recognize the image. An improved model of message entropy for land use was established based on the theory of information entropy and the feature of land use in city fringe. Through analyzing the distribution characteristics of entropy, the range of city fringe in Nanjing was confirmed with the entropy values of 60 and 68. Then this paper concluded a comparative boundary between urban area and urban fringe. However, the paper also pointed out that the boundary of urban fringe is dynamic and in fact, subjective distinguishment with experience is needed in this process. This method has great feasibility in practice.